FHIR Server needs capability statements

[lmcnabb]

Identified need from May 2023 Connectathon & WGM:

We need to define our scope for our capability statement.  What I heard was: Every FHIR server needs a capability statement, really two.  1. API capability statement and 2. terminology capability statement.  For every operation you define - you need to describe.  From my notes if they make sense, you can do a few diff things:  It's being scoped out code that a server can use to declare capability statements, or client code declare what it wants to use, they are moving to a kind of coded grammar.  For people who want feature negotiation.  Could be part of modern app registration paradigm (e.g., terminology registration?)